n = int(input())
c = input()

cntR = c.count('R')

print(c[:cntR].count('W')) n = int(input()) n int(input()) int input() input c = input() c input() input cntR = c.count('R') cntR c.count('R') c.count c count 'R' print(c[:cntR].count('W')) print c[:cntR].count('W') [:cntR].count [:cntR] c :cntR cntR count 'W' cntR = c.count('R') c.count('R') cntR c = input() input() c n = int(input()) int(input()) n
n = int(input())
c = input()

cntR = c.count('R')

print(c[:cntR].count('W'))